Amanita muscaria (also known by the English-language common name fly agaric or Fly Amanita) is a psychoactiveagaric species of mushroom found commonly throughout much of the world. The quintessential toadstool, it is a large imposing white-gilled white-spotted, usually deep red mushroom, one of the most recognizable and widely encountered in popular culture. Though it is generally considered poisonous, Amanita muscaria is otherwise famed for its hallucinogenic properties with its main psychoactive constituent being the compound muscimol. The mushroom has had a religious significance in Siberian culture and possibly also in ancient Indian and Scandinavian cultures.Native throughout the temperate and boreal regions of the Northern Hemisphere, Amanita muscaria has been unintentionally conveyed to many countries in the Southern Hemisphere, generally as a symbiont with pine plantations, and is now a true cosmopolitan species.The common names in English, fly agaric or fly mushroom, are generally thought to derive from its European use as an insecticide, sprinkled in milk.[1] The flykilling agent is now known to be ibotenic acid.[2] Another compound isolated from the fungus is 1,3-diolein which is an insect attractor.[3][4] However an alternate derivation proposes that the term fly- refers not to insects as such but rather the delirium resulting from consumption of the fungus. This is based on the medieval belief that flies could enter a person's head and cause mental illness.